Valgus extension overload, also known as pitcher's elbow, is a common upper-extremity injury in throwing athletes. The condition occurs because the motion of throwing causes the humerus, located in the upper arm, to rub against the tip and fossa of the olecranon bone. The same forces also cause a stretching of the ulnar collateral ligament, also known as the medial collateral ligament.
In time, this movement leads to a wearing away of the cartilage that protects the olecranon. In the absence of cartilage, the exposed olecranon begins to develop abnormal growths known as bone spurs.
The condition typically presents with pain or swelling around the elbow area. In addition, athletes may develop weakness of grip and a loss of power or control in the throw. Damage may also manifest as a weakened grip and numbness in the fourth and fifth fingers.